Centering and installing a giant mirror

We recently purchased a Montclair Mirror from Z Gallerie for our dinning room. It's heavy (48 lbs) and large (36.25"W × 1.5"D × 53"H).

In order to hang it, I had to buy special concrete screws, and I had to calculate the optimal center relative to the wall dimensions, existing furniture, and stud locations. This took a few minutes to sketch out and calculate.

Ironically, upon seeing the mirror for the first time, my Wife's best friend commented how it was not centered! That's when I busted out my da Vinci diagram to show her that it was. She was probably thrown off by the fact that the light fixture is what is not centered in the room.